<intentionally top posting, as I didn't see a good place to make this comment within the previous text>
About the only thing I'd add to what others have said is that they now make SSDs in a different form factor -- if you look for them, they start with an M, iirc -- they are in the same size range as an SD card (well, a regular one, not a micro). You need a special socket to plug them into, and I'm not sure which (if any) single board computers (I'm trying to use that to refer to computers using a system on a chip) have that kind of socket. <nothing added below here> On Tuesday, June 18, 2019 09:14:19 AM Andy Smith wrote: > Hi Erik, > > On Tue, Jun 18, 2019 at 02:26:57PM +0200, Erik Josefsson wrote: > > As far as I understand, it is quite recent that SD cards are fast and > > large enough to be able to carry and run an entire Debian instance. > > Not really recent. I've run Debian sarge on a 128MiB CompactFlash > card and I'm sure people have done more extreme things than that. > > > If this is the case, maybe there is only theory available regarding > > whether you can make a computer "run faster" on a 64GB SD card than on a > > 32GB SD card when cards are otherwise identical. > > So firstly, SD cards in the general case aren't that performant or > reliable. You can spend more money to get faster and more durable > ones. The unique selling point of SD cards is the form factor – > they're small and have no moving parts. They're meant to go in > devices like cameras, dashcams, cell phones, etc. > > Given two SD cards that differ only in capacity, I would not expect > their performance to differ. The bigger one may last longer (survive > more writes) due to you using less of its capacity. > > > I don't really know how swap works on a standard computer, even less how > > it works when the whole computer runs from/on a SD card. > > It doesn't work any differently, except that swapping onto SD > generally isn't great because they aren't that fast and they often > have fairly low write endurance. > > SD cards aren't like SSDs, even though they are both made from a > form of flash memory. Modern SSDs and flash drives have much better > write endurance than modern SD cards. > > > Swap is supposed to be make your computer pretend that you have more RAM > > than it actually has, but if the whole computer is running from/on RAM > > (or is it?), then what does swap mean? > > I don't know why you have introduced the concept of a computer > running from memory, as that is a completely different topic. A > computer running from SD card isn't much different to a computer > running from an HDD or an SSD. It's just a block device. > > Now, due to the low write endurance of your typical SD card, some > people — especially those making small single-purpose devices — do > configure things to load off of the SD card into memory and then run > largely from memory. This prevents writes into the SD card, thus > prolonging its life. But that tactic is not in any way required when > using SD cards and can be done with any block device. > > > On Teres-I with redpill RC2 (now there is a RC3 that I have not yet > > installed) an unfortunate website with pop up commercials (like dn.se) > > can eat all performance there is and freeze the mouse for hours. I would > > guess that could have been fixed on a normal computer with "more RAM", > > i.e., "more swap"? But is the same true for e.g. Teres-I? > > Sorry I am unfamiliar with Teres and redpill. > > > Second question is if it is meaningful to buy a "super duper blazing > > fast" SD card for the task to run a whole Debian system? > > If you wish to run a general purpose operating system off of an SD > card then yes I would suggest that the fastest and more durable one > you can afford would be a good idea. But also consider a regular > SSD as some of the low capacity ones may compare favourably in > price with a specialist SD card. > > > There is a very expensive 64GB SD card from SanDisk that is called > > Extreme Pro that costs twice as much as same size Extreme Plus. Specs > > say it is "super duper blazing fast" for video in "Ultra HD 4K", but > > would Pro also be faster than Plus for the task of running Thunderbird > > and Firefox at the same time? > > Running big apps like that will benefit more from having enough > memory. After that is satisfied, fast storage will certainly help. > You'll have to look at the exact specifications of Plus vs Pro. > > What are you trying to achieve? > > Cheers, > Andy
